Modular DC-DC converter for high-performance fuel-cell systems in trucks and buses

摘要

Currently the industry is facing a massive push towards PEM (Polymer Electrolyte Membrane) fuel-cell based powertrains for heavy-duty trucks and buses. These applications are putting additional and new requirements on the DC-DC converter and other electronics of the PEM fuel-cell system. The biggest challenge for a DC/DC converter in a fuel-cell based powertrain for heavy-duty trucks and buses is the requirement of 800V output voltage in addition to the power level which is 2-3 times higher as compared to passenger car powertrains. Coupled to that, the number of fuel cell systems (FCS) in a truck could reach up to 3 units. Ideally one DC-DC converter could be used for these 3 FCS units, but this requires a change in DC-DC converter connection and currently this is not present in the market. In addition, DC-DC converters have to meet further technical requirements, mainly efficiency, durability or degradation, vehicle integration and lifetime. These requirements in combination with the requirements on the operation of the fuel cell accessories on 400V result in a new architecture for the DC-DC converter, which is currently not available on the market. AVL will present in this paper the latest results of its internal R&D project for a modular and scalable DC-DC converter that is targeted for commercial vehicle applications and provides additional special features. The DC-DC converter technology is intended to be flexible so that it can be customized for different power levels and also operating voltages as per the vehicle application.